There are pretty much two types of shooters. The first one knows how important a good dust cover is and they are running the right one. The next kind of person thinks that they are immune from old Mr. Murphy, and the inevitable won't happen to them. The wise shooter knows that a quality AR-15 ejection port cover is a must-have on any weapon you depend on.
Eventually, you will take a header in the muck, or some trash is going to try to get into your AR-15. When that happens, if your gun is wearing an excellent AR-15 ejection port cover, you can get up and keep firing. However, if you happen to be the second type who thinks it won't happen to me, then guess what? You just cost yourself some time. In the best case, it means tearing down your weapon and cleaning it out. Worst case, your day is over. You either can complain about bad luck or do something about it.
When you think of a NiB-X AR-15 Dust Cover Assembly as insurance, it's a bargain. It's no secret that inside your AR-15 are some very precision parts. From the Bolt Carrier Group to the fire control assembly, mud, and trash can mean disaster. Even if your AR-15 doesn't lock-up tight as a drum, consider the wear that will shorten the life of all those expensive, internal pieces. A NiB-X AR-15 Dust Cover Assembly serves to protect your weapon when things get down and dirty. There's no way a sane person would drive around without car insurance. So, why would you take out your gun without an AR-15 ejection port cover?